Design, test, and implement an ongoing system of data accrual to serve as a resource for generating and testing hypotheses concerning effects of chronically used drugs. Monitor the accrued data for the purpose of identifying previously unrecognized effects of such drugs. Carry out ad hoc in-depth analyses of the data in order to evaluate hypotheses (both those arising from the monitoring and from elsewhere). Effect ad hoc studies outside the monitoring system to provide for further evaluation of certain hypotheses. Provide estimates of when chronically used drugs appear to be safe.